Suspension systems for automotive vehicles comprise stabilizers that are arranged between the vehicle chassis and the suspension of each wheel. These stabilizers are usually formed by a cylindrical element which incorporates respective housings at its ends for assembling joints, typically ball or elastic joints.
The stabilizer is a part which joins the stabilizer bar with the suspension of the wheel. Stabilizers belong to the kinematic chain usually formed by the stabilizer bar, stabilizer, suspension, and vehicle chassis. The stabilizer is the element responsible for transmitting the stresses generated by the stabilizer bar to the suspension of the wheel, and vice versa, generating a moment in the vehicle chassis that is contrary to the vehicle's roll moment, achieving greater lateral rigidity of the vehicle.
When a vehicle starts going around a curve, a centrifugal force causing the car body to tilt towards the outside of said curve, is generated, creating a roll moment. The stabilizer bar attached to the suspension of the wheel by means of the stabilizer in turn experiences torsion causing a moment opposite the vehicle's roll moment.
As explained above, the function of the stabilizer is to transmit the stresses generated by the stabilizer bar to the suspension of the wheel, and vice versa. This element consists of two articulations attached by means of a longitudinal body. The articulations can be ball joints or elastic joints. One of the articulations is in turn attached to the stabilizer or torsion bar and the other articulation is attached to the vehicle's shock absorber, also being able to be anchored to any other element of the suspension instead of to the shock absorber, for example to a suspension arm.
The stabilizer is made up of a usually metal or polymeric body with two kinematic centers at its ends which are the center of rotation of the articulations located at said ends. These articulations can be either ball or elastic joints.
If they are ball joints, an intermediate part is arranged between the ball joint and the body referred to as a seat, the function of which is to assure the positioning of the ball joint in the kinematic center, allow transferring stresses from, the ball joint to the body and allow the rotation of the ball joint with respect to the body. The seat is integrally attached to the body, so there is relative movement between the ball joint and the remaining components described up until now.
The ball joint has the function of generating three rotational degrees of freedom and attaching the assembly of the stabilizer to the stabilizer bar or to the shock absorber of the automotive vehicle. In addition to these two functions, there is a third function which is assuring the leak-tightness inside the articulation. This latter function also exists in the body of the stabilizer, because it is in these two components where the dust seal or bellows is anchored by means of the rings.
In the case of an elastic joint with 6 degrees of freedom, the articulation is integrally attached to the body of the stabilizer at one end and at the other end to the stabilizer bar or to the shock absorber of the automotive vehicle.
There are different types of stabilizers on the market which have different configurations according to each specific application. These elements usually have a series of requirements in common among them, particularly having a specific rigidity, weighing as little as possible, allowing the fastest assembly possible and costing as little as possible.
There are steel stabilizers characterized by being very heavy and having little resistances to corrosion, coating the body being necessary. An advantage of such stabilizers is their high rigidity.
There are also aluminum stabilizers characterized by weighing less than those mentioned above but having less rigidity.
Finally, there are plastic stabilizers which are characterized by weighing less and being more economical; however these plastic stabilizers require a larger volume to have a rigidity equivalent to those mentioned above.